I'm on a project that can't quite move past Rails 3.0.x at the moment but I've managed to convince them to move to at least Ruby 1.9.x and get off 1.8.
This required moving up the fabrication gem from 1.1.2 to the 2.x series but it looks like 2.0.1 is the highest I can go.
It appears that this version of `build_instance' introduced on 2.0.2,
self._instance = _klass.new(_attributes, without_protection: true)
breaks backward compatibility with Rails 3.0.x by passing the hash for the second argument.
Just thought you'd like to know in case you want to update your documentation.